This invention relates to a circuit arrangement for supplying a load which comprises a lamp, comprising means for generating a DC voltage provided with
input terminals for connection to a supply voltage source, PA1 rectifying means coupled to the input terminals for rectifying an AC voltage supplied by the supply voltage source, PA1 output terminals for connection to the load, PA1 a DC-DC converter connected between the rectifying means and the output terminals and provided with first inductive means, a first unidirectional element, and a switching element, and PA1 first capacitive means coupled to the output terminals.
Such a circuit arrangement is known from European Patent 0323676. In the switching arrangement described therein, the output terminals are coupled to a DC-AC converter for generating a current of alternating polarity from the DC voltage, which current can be used for supplying a lamp. The switching element of the DC-DC converter is rendered in turn conducting and non-conducting with high frequency during lamp operation. As a result, a DC voltage is present across the first capacitive means, with which the DC-AC converter is supplied. The known circuit arrangement is highly suitable for operating lamps, more in particular discharge lamps such as low-pressure mercury lamps. A disadvantage of the known circuit arrangement, however, is that the first capacitive means are charged with a comparatively strong current when the circuit arrangement is switched on at a moment at which the supply voltage has a comparatively high value. This comparatively strong current, also called inrush current hereinafter, can adversely affect the life of the first capacitive means and the life of other components which carry this current. If the supply voltage source comprises a safety cut-out, a comparatively high inrush current may also cause the safety cut-out to interrupt the supply voltage.